The problem with this is that it'd generally result in a bunch of lucky minors and would be indistinguishable from just having lucky nations off. Lucky isn't that large a bonus that it will turn AI Tirhut into the second coming of the Maurya Empire.
Note that people aren't asking for the default to be altered, but for the option to ALSO play a non-weighted version
This is a paradox title, the answer should be obvious:
Why not allow modding of the weights? if you want no weight, just put 0.